“In today’s age, people pretty much are attached to their smartphones and feel completely naked without them. The thumb, especially, is most commonly affected.”

Texting and other smartphone activity can stress the tendons in your hand.Shutterstock

Almost two-thirds — or 64 percent — of American adults now own a smartphone, up from 35 percent just four years ago, according to the Pew Research Center. It found young adults were the most avid texters, sometimes exchanging more than 100 messages a day.

The thumb is many people’s go-to digit for mobile typing even though it has less dexterity than the other fingers, Osterman said. The thumb’s base is quite constrained and vulnerable to the overall position of the hand so if you turn your wrist at a funny angle to hold the phone, your thumb will be affected by that awkward move as well, she added.

Too much typing can overuse the thumb’s tendons, causing tendonitis, or inflammation, which can lead to aching, cramping and throbbing in the area. The pain usually goes away if you stop the activity, Osterman noted. She compared it to “mommy thumb,” or De Quervain's disease, which sometimes affects new moms when they start to lift their babies frequently.

Another consequence could be osteoarthritis of the thumb, said Lynnette Khoo-Summers, a physical therapist and associate professor at the Washington University School of Medicine. The treatment for any repetitive overuse injury is rest and ice, she added.

Thumbs have less dexterity than other fingers, yet they're often our go-to digits for texting.Shutterstock

Here are some tips to prevent problems:

Stop the activity that’s aggravating things — stay away from your device for a while or take frequent breaks. “It’s OK to put your phone down. We shouldn’t be slaves to the machine,” Osterman said.

Use voice-to-text feature on your phone to give your fingers a break from typing.

Try typing with a stylus to cut down on the repetitive motion for your thumb.

Switch hands so that one hand isn’t doing all the work.

Place your phone on a table and type from there. “The worst position is where you’re holding it in one hand — palming it in your hand — and then using your thumb to do everything,” Osterman said. “Any position where the phone is at rest… is going to be less irritating.”

Try not to use the same muscles for other activities. For example, texting and then playing video games may not be a good idea, Khoo-Summers said.

If rest and ice don’t get rid of the pain, treatment options include putting the patient in a little splint that immobilizes the area for a few weeks and rests the tendons, or injecting medicine around the tendons to break up some of the inflammation, Osterman noted. Some people need surgery but that’s “very few and far between,” she added.

If you feel a sharp shooting or burning pain, or numbness and tingling, it could mean a problem related to injuring a nerve, which can be harder to treat, Khoo-Summers said.

Bottom line: give your hands a break.

“The thumb is essential for many things, from being able to use a baseball to writing to picking up things. But I don’t know if nature intended the thumb to text as much as we do,” Osterman said.